Method of making a catalyst



. that a is diflicult,

ARTHUR L. DAVIS, or LIBERTY, mrssovnr,

AND KENNETH n. .mcon, or HELENA,

, ARKANSAS, ASSIGNOBS TO THE UNITED STATES OF AMERICA.

METHOD OF MAKING A CATALYST.

- 1,386,555.. Specification of Letters Patent.

No Drawing.

To all whom it may concern Be it known that we, ARTHUR L. DAVIS andKENNETH D. JACOB, citizens of the United States, and residents ofLiberty, Clay county, State of Missouri, and Helena, Phillips county,State of Arkansas, respectively, have invented an Improvement in Methodof Making a Catalyst, of which the following is a specification.

This inventionrelates to catalysts which are especially adapted, amongother uses, to the synthetic manufacture of ammonia and has for itsobjects the economical production of durable, readily regenerablecatalyst, which is capable of producing excellent ields of ammoniathrough the synthesis of its elements therewith.

Heretofore in the preparation of molybdenum-iron catalysts for use inthe synthesis of ammonia, it has been customary either to evaporateconsisting of predetermined proportions of solutions of ferric nitrateand ammonium molybdate, after which the residue was ignited and reducedin either hydrogen, am-- monia, or nitrogen-hydrogen mixtures, or elseon the other hand predetermined amounts of ammonium molybdate solutionwere added to a ferric nitrate solution of own content, the solutionbeing main tained approximately, at room temperature, and the ferricmolybdate which was precipitated was filtered ofi", washed, dried,ignited and reduced as above.

en following the first, method above indicated, it has been found thatthe necessary evaporation and ignition resulted in retarding. thereduction of the product at the v relatively low temperatures-such asemplo ed in our process as hereinafter describe with the consequencethat rather low yields ofammonia were obtained-and the large scaleimportant employment of such processes was prevented. 'On the otherhand, the employment of the second method above described results in theproduction of a final product of such varying composition,

if not practically impossible, to obtain a definite and predeterminediron and molybdenum content.

Our investigations have led to the discovery that it is ossible toproduce a catalyst oftheso-cal ed iron molybdenum type,

which is homogeneous, of definite predetermined composition with respectto its iron- -ture is heated to the boi to" dryness a mixture carrieras' lime,

I Patented Aug. 2, 1921.

Application filed January 3, 1920. Serial No. 1349,2805.

and molybdenum content, rugged in form, res stant to ordinary contactpoisons, easily regenerable, and which will produce excellent yields ofammonia.

In the manufacture of our improved catalyst, we preferably proceed asfollows: 7 1085 parts of ferric nitrate are dissolved in 1500 arts ofdistilled water and heated to 50 To this solution is added slowly withstirring 300 parts of ammonium molybdate dissolved in a mixture of 500garts ammonium hydroxid and 1000 parts istilled water. The slightlyacidified mixing point and then filtered through a suitable filteringmedium. The precipitate is thoroughly washed with distilled water asrapidly as possible, then dried and ignited. This resultant product isthen ignited and reduced directly by hydrogen, ammonia or a nitrogen andhydrogen mixture.

The ignition is at from 500 C. to 800 C. and preferably the reduction iscarried out between about 450 C. and 600 C. for from about 5 to 100hours, the period being determined by the degree of reduction desiredand the temperature em loyed. We have obtained equally good yie lds whenthe mixture was ignited at either 800 C. or 500 (1., and the reductioncarried out at either 600 C. or 450 C. respectively.

The synthesis of ammonia from its elements by the employment of theaforesaid catalyst is preferably carried out at increased pressure inaccordance with well known methods. The catalyst may be formed in coarseparticles, of homogeneous composition or may be distributed upon aasbestos, magnesia, etc.

Having thus described our invention, what we claim and desire to secureby Letters Patent of the United States is: 1. The method of preparing acatalyst for chemical synthesis, including preparing a solution offerric nitrate, slowly adding to this solution, while stirring, asolution of ammonium molybdate dissolved in ammonium hydroxid anddistilled water, heating the resultant mixture to the boiling oint,filtering, immediately washing the filtrate, drying the same,thenigniting and reducing the resultant product.

2. The method of preparing a catalyst for chemical synthesis, includingpreparing a solution of ferric nitrate, slowly mixing therewith whilestirring a solut-ion'of ammonium molybdate, heating the resultantmixture to the boiling point, filtering, washing the filtrate drying thesame, then igniting and reduclng the resultant product.

I 3. The method of preparing a catalyst for chemical synthesis,including preparing a ferric nitrate, mixing therewith a solution ofammonium molybdate, heating the resultant solution to boiling point,filtering, washing and drying the filtrate, then igniting and reducingthe resultant product.

4. The method of preparing acatalyst for chemical synthesis, includingmixing solutions of ferric nitrate and ammonium molybdate, heating tothe boiling point, filtering, washing and drying the filtrate, ignitingand reducing the resultant product with a fluid free from 'catal ticpoisons.

5. The method 0 preparin a catalyst for chemical synthesis, inclu 'ngmixing solutions of ferring nitrate and ammonium molybdate, heating tothe boiling point,

filtering, washing and drying the filtrate;

igniting and reducing the resultant product with a medium includin hdrogen.

ARTHIfiQ DAVIS. KENNETH D. JACOB.

